GM 880 Engine block

[ScaryLarry]

Has the GM 880 engine block been used in a production engine? Seems like the only ones that have the mechanical fuel pump feature is on the 602 crate engine.

[rfoll]

Some blocks have it some don't. The 880 block showed up in cars and trucks around 1987. Many marine applications have to use a mechanical fuel pump.

[68maliblue]

I have an 880 block that was cast in 1996. Its a two bolt main sgi block cast in Canada. It is drilled and tapped for factory roller cam and is fully drilled for a mechanical fuel pump. May have been a replacement motor. It was set up with flat tappet cam and had a tbi style timing cover.

[Eroy]

I've seen plenty of 880 blocks with mechanical fuel pump provision and hole. But, I also just had one drilled that didn't have it.

[Schurkey]

GM kinda does what they want. They have external customers (Mercury marine, for example) beyond their own assembly lines and parts departments.

What I have seen is that the 880 blocks WITH the fuel pump provisions tend to be 4-bolt main also, and may even have the old-style drillings for coolant bypass from the right cylinder head deck to the right-side water pump flange. Sort of the best of all possible worlds.

The 880 blocks along with most of the '90s-and-newer iron work are nicely detailed, minimal casting flash, etc. I don't know about the quality of the iron itself...but bore wear doesn't seem to be a particular issue. I don't know if the durability of the bore is due partly to the iron quality, along with the precise fuel control (no cylinder wash-down removing oil) and overdrive transmissions (less RPM per mile.)

The downside is the short cylinder barrels. Less than optimum for stroker cranks, but as pistons get shorter so they don't poke out the bottom as much, it's less of an issue.

I bought a "service replacement" 5.7L engine for a '91--'93 TBI Caprice/Roadmaster. 880 block, 2-bolt mains. Roller cam including spider and thrust-plate, coolant bypass drilled and TBI timing cover with all holes drilled and dowel pins installed. NO fuel pump provision. When that popped a head gasket and gouged the block and head, I bought a core engine from a Vortec truck to rebuild. Also 880 block, 4-bolt main, roller cam. Vortec timing cover with 2 holes missing, no dowel pins. Has fuel pump provision and coolant bypass.

I think this is a case of GM using one casting number with various machining operations to make multiple part numbers.

[rebelyell]

seems current "service replacement" completely new Goodwrench L31 vortec 5.7L motors are all USA, 4 bolt main, steel crank, complete fuel pump pad; manufactured by GM partner SRC Springfield MO USA ... during Trump admin, NAFTA was dumped & replaced by USMCA ... soon thereafter GM moved much Mexico engine production to Springfield. However, dunno if current L31 block is "880" casting.
https://www.srcautomotive.com/

[Justa1time]

Two blocks ago I had a vortec 350 from a late 90s gm van. Very nice block. I was insistent on a mechanical fuel pump. The block had the casting provision; however, did not have the pin boss machined. I live in the center part of Oregon. The block was sent to the willamette valley for someone to drill it & the block came back not drilled. Allegedly some of the 880 blocks have a pin machined but NOT all the way through the casting & a jig can be had to pilot off that existing pin boss and drill through to complete the passage. My block didn't even have a pin boss bore started. Another shop in Aurora said they perform this process on the 880s primarily for their marine customers and have a cnc specifically set up for the job. I needed this process done during covid & the machine was down waiting on a circuit board replacement with no ETA. I waited about 7 months! Then gave up.

I ended up selling this block and sourcing another engine entirely that had the mechanical fuel pump ready to roll. This was probably a bad move on my part because the block I currently have with the pin bore in tact had to go .060" over & had head bolt provision issues along with other issues that I am still living with.

Ah to what lengths to get a mechanical fuel pump 880 block.

Always the option of the marine belt driven mechanical pump. Eek $800!

Another noteworthy point is the only decent adjustable cam timing set is the cloyes hex-a-just.

I really wanted the quick adjust with multiple fasteners to lock it in place. They don't offer this for the 880 blocks.

Bryan

[Tom68]

Carter electric P4070 all but bolts to the bolt holes in the fuel pump boss, makes the lines easy being down there.

No fuel pump pushrod hole also mean no oil drain back hole in there either, turbo guys will know that.

[notched]

I was always under the impression that the 880 block was a mid 90's and later casting. The 638 was the common 350 casting from the late 80's to the mid 90's.
Speaking of 880 blocks. I have a 2 bolt 880 block with a machined fuel pump casting in my Malibu at the moment. I found it at my favorite core supplier before he retired and closed up. It is a 1995 casting from a tbi truck.

[turbo camino]

^^^ Same, mine is also from a 1995 pickup truck and was fully machined for all the things even though it didn't use them (FP, roller cam).

There's nothing special about the 880 block regarding timing sets, cam gear just has to match the cam type (step nose or retrofit/non-stepped).

[turbo camino]

Bolt spacing for the cam retainer plate can be either narrow (1st design, 3.294") or wide (2nd design, 3.620"). There's no way to tell from the outside which a particular block has without tearing it apart and checking.

[rebelyell]

I was always under the impression that the 880 block was a mid 90's and later casting. The 638 was the common 350 casting from the late 80's to the mid 90's.
Speaking of 880 blocks. I have a 2 bolt 880 block with a machined fuel pump casting in my Malibu at the moment. I found it at my favorite core supplier before he retired and closed up. It is a 1995 casting from a tbi truck.

How does the length of 638 cyl liners compare to those noticeably short 880 liners ? Anyone compared lengths of both ?

[Racer97]

638 that I had was a full length cylinder, better for a 383 build.

[Bill Chase]

I've got two cores in my garage. Both 96/97 L31. Weird the bolt holes are drilled but the pushrod hole for the pump is not machined. Both 2bolt mains.